1. Field of the Invention
The present invention is generally related to a tilt, or trim, system for a marine propulsion device and, more particularly, to a method for programming an upper limit for the trim position of an outboard motor in a way that facilitates a precise setting of an end-of-travel position beyond which the outboard motor will not subsequently be tilted.
2. Description of the Related Art
Many different systems are well known to those skilled in the art for the purpose of trimming or tilting a marine propulsion device.
U.S. Pat. No. 4,051,801, which issued to Woodfill et al. on Oct. 4, 1977, discloses a drive position signaling apparatus. A marine jet drive includes a nozzle which is mounted in a gimbal ring for pivoting about a horizontal axis for trimming of the drive jet. An electric motor drives a gear train including a rotating actuator shaft having an Acme nut actuator connected by a rigid linkage to the gimbal ring for trim positioning of the nozzle. A potentiometer is mounted within the gear housing with an input shaft parallel to the actuator shaft.
U.S. Pat. No. 3,722,455, which issued to Carpenter on Mar. 27, 1973, describes a hydraulic power trim and power tilt system for a marine propulsion device. An outboard motor includes a first extensible hydraulic cylinder means pivotally connected between a transom bracket and a swivel bracket to afford power tilting and, in response to the striking of an underwater obstacle, to afford energy absorption, together with a second extensible hydraulic cylinder means having an extensible part and mounted on the transom bracket with the extensible part positioned for engagement with the swivel bracket to afford trim adjustment.
U.S. Pat. No. 5,073,133, which issued to Inoue on Dec. 17, 1991, describes a fuel supplying system for an engine of an outboard motor. An arrangement for insuring that an internal combustion engine of an outboard motor will operate efficiently under all trim adjusted conditions of the outboard motor is described. The trim angle is sensed and the fuel delivery system is adjusted to provide good running in response to the trim condition. Additionally, embodiments are disclosed wherein the fuel delivery system is also adjusted during initial starting so as to provide adjustment of the fuel delivery in response to both the starting condition and the trim condition. Both carbureted and fuel injected systems are described.
U.S. Pat. No. 5,142,473, which issued to Davis on Aug. 25, 1992, describes a speed, acceleration, and trim control system for power boats. A computer-based system controls speed, speed and acceleration and/or trim. Trim control is responsive to sensed inclination. Inclination/acceleration is sensed by an inclinometer/accelerometer having an electrically conductive fluid that flows within a conduit. The fluid assumes different positions in its flow path under differing gravitational and acceleration forces. A multiplicity of pins, positionally arrayed along the fluid flow path within the conduit, electrically sense the presence, or absence, of the fluid at a corresponding position within its flow path.
U.S. Pat. No. 5,662,213, which issued to Kattler et al. on Sep. 2, 1997, describes a trim switch with a waterproof boot. The trim switch is intended for mounting in an opening in an outboard motor cowl. The trim switch includes an outer housing which overlies a rocker assembly. The rocker assembly includes a rocker and a rocker support housing. The rocker support housing defines an interior region in which terminals and a terminal bridging contact are disposed.
U.S. Pat. No. 6,183,321, which issued to Alby et al. on Feb. 6, 2001, discloses an outboard motor with a hydraulic pump and an electric motor located within a steering mechanism. The outboard motor comprises a pedestal which is attached to a transom of a boat, a motor support platform that is attached to the outboard motor, and a steering mechanism that is attached to both the pedestal and the motor support platform. It comprises a hydraulic tilting mechanism that is attached to the motor support platform and to the outboard motor. The outboard motor is rotatable about a tilt axis relative to both the pedestal and the motor support platform. A hydraulic pump is connected in fluid communication with the hydraulic tilting mechanism to provide pressurized fluid to cause the outboard motor to rotate about its tilting axis. An electric motor is connected in torque transmitting relation with the hydraulic pump. Both the electric motor and the hydraulic pump are disposed within the steering mechanism.
U.S. Pat. No. 6,620,006, which issued to Suganuma et al. on Sep. 16, 2003, describes a trim and tilt control and cowling arrangement for a marine drive. The outboard motor includes a cowling substantially enclosing an engine therein. A tilt and trim mechanism includes a manually-actuable tilt switch for controlling tilt and trim of the motor. Both the port and starboard sidewalls of the cowling have apertures formed therethrough. The apertures are sized and configured to accommodate a tilt switch. In one embodiment, a tilt switch is arranged in one aperture and a plug is arranged in the other aperture. In another embodiment, tilt switches are arranged in both apertures.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
In a typical arrangement using an outboard motor attached to the transom of a marine vessel, limit switches of one type or another are provided in order to stop the rotational movement of the outboard motor about its tilt axis. This is particularly true with regard to the upper position of the outboard motor when it is tilted to raise the propeller of the marine propulsion device out of the water. In relation to certain styles of boat design, the outboard motor can be tilted upwardly to a sufficient degree that damage can occur within the rear portion of the marine vessel, or to the cowl, when upper and forward portions of the outboard motor are moved into contact with portions of the marine vessel or accessories located in front of the outboard motor. The proper positioning of limit switches in relation to this uppermost trim position is sometimes difficult to achieve. It would therefore be significantly beneficial if a system or method could be provided in which an upper tilt limit is set automatically without the need for limit switches to be accurately positioned and attached to the marine vessel or to a stationary portion of the marine propulsion device.